Designing a 19-gate, three-story aviation hub is a monumental architectural challenge. Bringing it to life while seamlessly maintaining passenger operations at the nation’s busiest single-runway airport requires nothing short of a perfectly choreographed airborne ballet. Yet, at the San Diego International Airport’s newly opened Terminal 1, the project team did more than just stick the landing–they redefined what is possible when architects, structural engineers, and steel fabricators collaborate from the very beginning.
Replacing a cramped, 1960s-era building, the new Terminal 1 boldly reimagines the passenger experience. It is a masterclass in how early coordination and structural steel can satisfy stringent seismic requirements, enable an open-space architectural vision, yield staggering material savings, and score major sustainability wins–as well as AISC’s 2026 IDEAS Award for Excellence in Constructability.
Collaboration that eliminates boundaries (and columns)
To achieve the terminal’s luminous wave landside façade and soaring, 27-ft-high ceilings without restrictive interior columns, the design required long-span steel framing. This openness was the result of a tight partnership between the architect, Gensler, and the prime structural engineer, Magnusson Klemencic Associates (MKA).
By pivoting early from a baseline steel moment frame lateral system to buckling-restrained brace frames (BRBs), the team unlocked immense spatial freedom. “We were able to use those long-span trusses and long-span structure to get rid of all the intermediate columns in the ticketing hall,” noted Terry Palmer, senior principal and aviation specialist group leader at MKA, underscoring the structural strategy that defined the terminal’s aesthetic.
In total, more than 100 columns were removed from the ticketing hall and airside concourse. MKA and Gensler worked hand in hand to integrate the BRBs symmetrically into the façade vision, showcasing the seismic load-resisting system with matching casing shapes and architectural column encasements.
Braced for impact: engineering beyond the limits
Not all buildings are designed for the same level of resilience. As a Risk Category III structure, this facility was engineered to withstand severe natural disasters while remaining operational when it is needed most. Built adjacent to an active fault and in a coastal environment, the project was designed to resist major earthquakes, sea-level rise, and tsunami hazards, setting a high standard for long-term performance and durability.
The team didn’t just use BRBs; they pushed the limits of the technology. Building adjacent to the Spanish Bight fault on liquefiable soil, the project required BRBs longer and larger than had been physically tested by U.S. manufacturers.
The economics of constructability
The success of Terminal 1 is rooted in its fast-track constructability. Fabricator design-assist was engaged at just 30% design. W&W | AFCO Steel, an AISC-certified full member fabricator, collaborated deeply with MKA to optimize tonnage, refine complex connection details, and streamline erection sequences before steel arrived at the active airport site.
The results of this proactive coordination speak for themselves:
- Cost savings: The Turner-FlatironDragados joint venture reported approximately $100 million in savings, driven largely by optimizing the building grid and floor loading.
- Material efficiency: The team achieved a 40% reduction in overall steel tonnage.
- Speed: Preassembled modular pedestrian bridges, roof trusses, and BRBs allowed 9,600 tons of steel to be erected in just six months.
- Phasing: Phased erection strategies minimized passenger disruption, completing Phase 1A before the original terminal was demolished.
A sustainable arrival
Structural steel’s strength-to-weight ratio and adaptability were vital in achieving the project’s LEED Gold ambitions and reducing global warming potential (GWP). A whole building life cycle assessment (WBLCA) verified the embodied carbon reductions, aided by strict bidding language requiring environmental product declarations (EPDs) and domestically produced steel.
Steel’s circularity was showcased in a unique adaptive reuse effort. A historic 1920s United Airlines hangar on the site was meticulously disassembled, relocated, and retrofitted. By splicing and reinforcing the original elements with a new, code-compliant special cantilever column system, the design seamlessly blended the airport’s heritage into its modern footprint.
The power of the team
From right-sizing vibration criteria using AISC Design Guide 11, Vibrations of Steel-Framed Structural Systems Due to Human Activity to incorporating elegant CAST CONNEX steel castings on the 100-ft pedestrian bridges, every detail of Terminal 1 highlights the power of early integration.
“Having structural designers and the steel fabricator team up at the beginning of the project ensures innovative constructability, “ said IDEAS Awards juror Courtney Lilly, QA/QC supervisor at Southern New Jersey Steel.
As the airport looks toward the completion of its 11-gate Phase 2 in 2028, the newly opened Terminal 1 stands as a soaring testament to architecture and structural steel. It proves conclusively that when design and construction disciplines break down their silos from day one, they can build highly resilient structures that elevate the human experience, respect the environment, and arrive safely on time and under budget.
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Explore more about San Diego International Airport Terminal 1 and four more recipients of AISC’s 2026 IDEAS Awards at aisc.org/ideas. And enter your project for the steel industry’s most prestigious design award today. It’s free to enter, and the deadline for 2027 submittals is August 31!
